1. Field of the Invention
This invention relates generally to communication systems, and, more particularly, to wireless communication systems.
2. Description of the Related Art
Wireless communication systems typically include one or more base stations, access points, or base station routers for providing wireless connectivity to mobile units. One of the most common types of mobile unit is a cellular telephone, which is typically used for voice communications between people. Other than the fact that the cellular telephones transmit signals over an air interface between the mobile unit and the wireless network, cellular telephones operate very much like their conventional wired counterparts. In particular, cellular telephones ring, or provide some other kind of auditory signal, to indicate an incoming a call. Although a ring can be a very effective signal in some contexts, in other contexts the unexpected ringing of a cellular telephone can be a cause of great annoyance and/or embarrassment. For example, a cellular telephone's ringtone rendition of Tchaikovsky's 1812 Overture may be particularly unwelcome during a performance of Barber's Adagio for Strings.
Mobile units may be operated in either a silent mode or a vibration mode so that incoming calls do not cause a sound to be produced. Visitors to public places, such as restaurants, hospitals, movie theaters, and the like, are often requested to set their mobile telephones in the silent mode or the vibration mode so as not to disturb the other visitors. Even though a majority of people set their phones in the silent mode, very often people either forget to set their phone in the requested mode or deliberately leave the phone in the ringing mode. In either event, ringing of these phones may cause embarrassment and/or irritation. Jamming of incoming radiofrequency signals may be used to disable mobile terminals and/or to prevent any incoming calls from reaching the cellular phone. However, jamming also prevents urgent calls from reaching users and prevents users from placing emergency calls.
One potential solution to this problem is to use a Bluetooth transmitter to provide a signal to instruct Bluetooth-capable cellular telephones to switch from the ringing mode to the silent or vibratory mode. However, Bluetooth is not the primary wireless communication medium for cellular telephones. Many cellular phones do not include a Bluetooth interface and, even if the phone does include a Bluetooth interface, users may turn off the Bluetooth interface. Consequently, many phones may not be capable of receiving signaling over the Bluetooth interface and therefore will not “receive” the instructions to switch from the ringing mode to the silent or vibratory mode. Furthermore, the range of Bluetooth transmissions is typically limited to less than approximately 30 m.